Air tightness testing, also called air leakage testing or air pressure testing, calculates the quantity of air escaping through openings in a building. Air tightness testing has been a compulsory part of the building regulations for new dwellings, renovations and commercial projects since the revision of Document L in 2006.
Because air leakage is the process whereby air escapes through any crack or hole in the building envelope and influences its energy performance, building regulations have been modified to ensure a building has adequate air tightness. AF Acoustics certificates are certified by Air Tightness Testing and Measurement Association (ATTMA). ATTMA is an association of specialists that concentrate on promoting the best air tightness measurements and air permeability testing techniques. Located in Harmondsworth, our company is a committed and accredited air permeability testing service provider; we provide air testing services. You can also call or email us for any of these services:
As registered members of the ATTMA, our air tightness certificates are accepted as proof of building regulations sign-off. If you want specialist air pressure testing services in Harmondsworth, AF Acoustics’ tightness testing services will
Our customers get greater value for money spent, and our testing services are of superior quality.
Air tightness testing is a technique whereby a newly constructed building is evaluated and the quantity of air leaking through is measured. It is sometimes referred to as air leakage testing or air pressure testing. Air leakage is the draught or infiltration of unbridled air through the spaces and openings in a building. It is different from ventilation, which is the contained circulation of air within and outside the building. Air tightness testing is the recognised method used to measure total air lost through leaks in a building fabric. This is often referred to as uncontrolled ventilation (draughts). Too much air leakage leads to unnecessary heat loss and discomfort for the occupants. Regulations now concentrate on minimising air leakage from the building envelope thereby reducing the amount of fuel burned for maintenance. This helps reduce carbon dioxide emissions. With air tightness testing, you can determine whether or not air is leaking from a building’s envelope, the build quality and energy efficiency of new developments. The building regulations have made air tightness part of the building’s design from the beginning of the construction. This ensures that the fabric of a building is air tight. Understanding this at an early stage can make a build cost-effective, of high quality, and energy efficient by minimising uncontrolled air leakage.
Air leakage is uncontrolled air movement in a building due to cracks. Air leakage is the uncontrolled movement of air into and out of a building through gaps and spaces in the building’s fabric. Also called infiltration, it differs from ventilation which is the regular, planned and restrained flow of air into a building. Once the atmosphere is windy, draughts infiltrate the building through holes in the fabric, leading to heat reduction and discomfort. Air leakage testing plays a significant role in the energy-saving efficacy of properties. With air tightness testing, you can be sure that the building has met the stipulated targets used for energy calculation and air tightness. Air tightness testing is compulsory for all new constructions and non dwellings with a floor area over 500m² in England and Wales. This came into effect in 2006.
Heat loss within a building can be caused by air leakage. During windy or cold weather, the infiltration of uncontrolled air through cracks in a building envelope occurs, leading to heat reduction. Once there’s infiltration, exfiltration will occur in another part of the building. Warm, moist air seeps into cool cavities in the building’s fabric. The warm air is filled with moisture, which hits the inner wall surface and condenses. Moisture is sucked into the building material, and this can lead to serious structural issues. Wooden sheathing or overlay becomes wet, making it weak.
The building becomes structurally damaged as time goes on.
Air leakage can also cause these problems:
Successfully managing the movement of air into and outside the building will limit the damaging effects of moisture. Air leakage and vapour diffusion are minimised when barriers are installed. Proper ventilation, whether active or passive, is critical in expelling undesirable damp scents, water vapour and polluting substances.
Air tightness is an important factor in a building’s energy efficiency and is part of government’s plan to battle environmental change by regulating the energy performance of buildings. Heating buildings contribute to global warming and CO2 emissions, since fossil fuels are used to create heat. The reduction of air leakage leads to lower heat loss and quantity of heat generated in a building. There are also health issues associated with uncontrolled air leakage. When a building has poor levels of controlled ventilation and high levels of uncontrolled air leakage, this can cause excessive moisture and mould growth, leading to poor health. To “Construct tight, ventilate right” is the best practice. The result of uncontrollable air moving into the building fabric could be health problems and costly repairs.
Best practice says that air tightness tests should be carried out early in construction and after the final phase. The test results are part of SBEM and SAP calculations, therefore they influence the total energy ratings of new buildings. Large residential areas do not need each building to be tested. Instead, different types of dwellings are tested. This type of testing attracts a penalty of +2m3/h/m2, consequently, if the target result is 5m3/h/m2, a lower score of 3 would have to be attained.
If your building has not been pressure tested, its assessed air permeability would be the average score of buildings like yours in the area +2m3/h/m2 at 50 Pa. Selective testing is not advisable, as it does not give a realistic picture of the air tightness of each individual building. A tested property might be a lot tighter than an untested property. Also, the penalty implemented on the untested houses make air permeability rates very difficult to achieve.
With AF Acoustics, homes and businesses in Harmondsworth have been getting quality air tightness testing. Our clients highly recommend us for the following reasons.
Our vast experience in serving a variety of clients in Harmondsworth guarantees we have the expertise to satisfy your needs regardless your unique circumstances, type or size of property. Our accredited air testing experts are polite and competent. They are trained to provide the service you need and fit around your project. Do you need trustworthy professionals who will provide great results in Harmondsworth? Contact AF Acoustics today.
We are registered members of the Air Tightness and Measurement Association (ATTMA). ATTMA encourages proper air leakage applications and promotes quality air tightness screening, and has recognised our impeccable professional services.
We want to provide detailed air permeability testing in Harmondsworth for you whenever you need it. We have responsive scheduling options. Schedule for your air leakage testing at your comfort. We guarantee that there will be no delays or difficulties.
AF Acoustics has professional speedy services to satisfy clients who want their test results immediately. We have a next day turnaround policy for our test certificates and endeavour to deliver in all situations.
At AF Acoustics, we offer the most competitive prices in Harmondsworth to ensure you have access to affordable air tightness testing when you need it. We keep the costs down, as we are a small business with low overheads. This allows us to be competitive with our pricing whilst guaranteeing a professional service.
All domestic and commercial buildings in Harmondsworth can be tested by AF Acoustics, no matter how complex they are. The air tightness tests are carried out by competent testers and you will be issued an ATTMA certificate. You can find out how much uncontrolled ventilation your building has by testing it for air leakages. The test results are described as The test results are described as m3/h/m2 – (m3 per hour) per square metre..
Air leakage testing is a requirement of Approved Document L1A and L2A. The design-stage SAP assessment or SBEM of a construction records its required air permeability rate. While the law requires the highest air permeability rate to be 10m3/h/m2, your building might have to get a lower rate to meet the carbon emissions target. Excess air leakage causes heat loss, greater carbon dioxide discharge and can make occupants uncomfortable due to the influx of cold air. It also causes wind washing and thermal bypassing, resulting in lower energy performance. Exfiltration/infiltration of air is caused by a stack effect. Due to the pressure difference inside and outside the building, rising warm air reduces the pressure in the base of the building and draws in air, whether through open doors, windows or other openings and leakage points. Air permeability testing is a legal requirement for constructions in Harmondsworth. This way, they can have high energy performance, meet building regulations requirements and get signed off by building control. For commercial constructions, air pressure tests result in a better environment for workers and customers. It will also help you reduce the cost of maintaining heating or cooling in your commercial building, making it more productive.
Since Approved Document L was reviewed in 2006, building regulations have demanded that new and rehabilitated constructions conduct air tightness test. The air-tightness of a building is known as its ‘air permeability’ or leakage rate. Although not always seen, air leakage can occur through any gap, space or crack in a building’s fabric. Samples of houses in an area and all non-domestic buildings with more than an area of to m2 must be tested, according to Part L of the Building Regulations. Part L has also set a maximum air permeability target rate of 10m3/h/m2, but a building usually needs lower levels. Air leakage affects the building’s energy performance and is required to meet Building Regulations Part L and measure up to the standard for low carbon buildings.
We will ensure that you exceed all the Parts L and F standards. First, we provide extract fan flow rate and air leakage testing. Then we put you in contact with competent professional to work on your Energy Performance Certificates, SAP and water calculations.
New buildings should ensure that all mechanical extract fans are tested for flow rate, as stipulated by Part F of the Building Regulations. The Building Control Body (BCB) has to see the results of the test as part of its sign-off procedure. There are three alternative methods which can be followed to test, record and report the testing of extractor fans. Using a vane anemometer, our testing procedure follows Method 3 – The minimum benchmark method.
There are several levels of air leakage testing based on the kind, size and multifaceted aspects of a dwelling. Here they are: A single blower door fan is the instrument used for the first level to examine single buildings and smaller non-dwellings from 1m3 to 4000m3. The second level examines simple and complex buildings greater than 4000m3, with the exclusion of large zonal buildings and complex high rise (LCHR) buildings. Third Level – Testing is done for large high rise and phased handover buildings.
An air leakage test is a test to determine the level of uncontrolled air flow through gaps or cracks in the fabric of a building. The test results are inscribed as m3/h/m2 – (m3 per hour) per square metre. Air pressure testing is compulsory, according to Approved Document L1A. Your building may need a lower rate to meet the CO2 discharge target. The required air permeability rate for a dwelling can be found on the design-stage SAP report for that dwelling. Too much air leakage leads to heat loss which can lead to draughts and higher energy bills.
Air tightness testing determines the extent of air leaking from a building’s envelope. The air leakage test result is written as m3/h/m2 – (m3 per hour) per square metre of building. Air leakage testing is a requirement of Approved Document L2A. The maximum air permeability rate for a dwelling tested is 10m3/h/m2. In order to comply with the SAP assessment, it may be necessary to achieve a lower air permeability rate. To get your building’s required air permeability rate, check its design-stage SAP or SBEM assessment. Excess air leakage causes heat loss, greater carbon dioxide discharge and influx of cold air.
We undertake smoke shaft integrity testing to confirm that the shaft is sufficiently air tight in order to allow the automatic opening ventilation to perform as required when it is fitted and commissioned. Smoke needs to be cleared out in the event of a fire. The automatic opening ventilation is a vital aspect of the fire strategy for high rise buildings. For it to expel smoke from a building and keep the occupants safe during emergencies, the shaft must be air tight enough to create substantial pressure difference. We work towards air permeability targets set by the automatic-opening ventilation manufacturers that allow their equipment to operate effectively. The shaft is tested for air permeability by using a fan that is fixed inside it. The intended openings of the shaft (i.e. extract point and openings for ventilation grilles on each floor) are sealed off for the test so that the integrity of the shaft itself can be determined. Smoke shaft tests occur before installing and commissioning automatic opening ventilation.
With the legal requirement for buildings that have the right quantity of air pressure, adequate ventilation that is suitable, effective and of high quality has become crucial. We are able to test extraction rates. This has not only been made compulsory by Building Regulations; it also helps reduce humidity in rooms, bathrooms and kitchens and expel pollutants. The air flow rates of all intermittent extractor fans, which are to be installed during the building process, are to be tested and the results submitted to the Building Control Body before work is completed.
Air tightness test determines the level of air permeability in a building. When air leakage is reduced in a building, the occupants will not experience discomfort and the energy performance will increase.
Causes of excess air leakage are often hard to detect. These openings might not be seen because of the internal finishes that have been fixed. If you know the leakage paths of a building, you will know if it is air tight.
At least 20% of different kinds of dwellings in a development have to be tested, according to new regulations; but the reliability of the sample from this type of testing is determined by the types of buildings in the development. We recommend that all dwellings be tested, as there is a penalty for developments that are not tested.
Clients should send the drawings (plans and elevations) and air permeability requirements to our engineers. We would like to know the requirements and the building envelope’s size prior to testing. The tests take 30 – 60 minutes, and wind speed does not surpass 6m/s. To prepare the site for the test, do the following:
Before coming to the site, we get the measurement of the building’s envelope. The building envelope is the surface area of the structural barrier of a building. It separates the interior from the exterior part of the dwelling The calculations are taken from the drawings. These are then incorporated into our calculations when we air test the property.
It is defined as air leakage rate per hour per square metre of envelope area at the test reference pressure differential of 50 pascals (50n/m2). The envelope area, or measured part of the building, is the total area of all floors, walls and ceilings bordering the internal volume that is the subject of the pressure test. This includes walls and floors below external ground level. Overall internal dimensions are used to calculate this envelope area and no subtractions are made for the area of the junctions of internal walls, floors and ceilings with exterior walls, floors and ceilings.
Air exchange rate is vital to ventilation design but it isn’t used as the determinant of the actual design or calculation. The number of inhabitants and area of residence are used in measuring residential ventilation rates.
Measuring if the roof area and ground floor area of a building are the same is vital. A cold roof has its insulation at the ceiling level, with space between the insulation and rafters.
A warm roof is a roof system where the insulation is fixed along the rafters with an air barrier inside the insulation. The envelope area, found at the insulation’s warm side, is the separator between the conditioned internal aspect and the unconditioned.
Measure the weather conditions. Check the temperature, barometric pressure and wind speed. Connect a fan (or fans) to an aperture in the building envelope (e.g. door). Set up the equipment for air tightness testing. Note the air flow volume from the fan. This is the same as the air leakage from the building envelope. Raise the fan speed from 20-25Pa to the highest speed of 55-60Pa. The pressure differences in the building at each fan speed should be calculated.
We analyse the recorded air tightness test data and present the results to the client in a technical report. In the event of test failure, we advise the client on appropriate mitigation measures. Our expert knowledge will help in highlighting the areas of air leakage. Air Leakage Testing and Compliance
Making sure your building is air tight and has adequate ventilation, be it natural, mechanical, or a combination of the two, will aid your comfort. Find below the benefits: Lower heating bills due to less heat loss, with potentially smaller requirements for heating and cooling equipment capacities Better ventilation system Lower probability of mould because moist air won’t condense in the openings in the building envelope. Infiltration of air is reduced and the inhabitants are more comfortable. Our clients can expect a stress-free conformity to Part L Building Regulations standards, whether they have a single building or a large commercial building. Our services include: air pressure testing, support services, re-examining designs and consultancy for all buildings in Harmondsworth. We are cost effective and adhere to all building regulations.
Any new building has to be air tight. The 2010 Approved Document L1A of Building Regulations has made it compulsory. This regulation was put in place to conserve fuel and power. Part L1A states that new dwellings should be tested for air tightness in accordance with existing regulations.
ATTMA has specified technical standards that must be adhered to while testing buildings in the UK, according to building regulations and other documents. The technical standards give details regarding the following: BS EN 13829:2001: “Thermal Performance of Buildings. Determination of air permeability of buildings. Fan pressurisation method” and ISO 9972:2015: “Thermal performance of buildings – Determination of permeability of buildings – Fan pressurization method”. That way, testing companies use the same method.
Approved document L1A has made it compulsory for all new buildings to be tested for air leaks. Those exceptions only occur when there are two or more dwellings in a development. Three units of a dwelling type or 50% of all examples of that dwelling type should be tested. Where there are only one or two new buildings, add an assumed value of 15m3/h/m2 to the DET/TER measurements; an air tightness test may not need to be carried out. To find if your building falls into this category, contact your SAP assessor. The required process for testing buildings for air tightness has been declared in ATTMA TSL1 for occupied buildings and ATTMA TSL2 for unoccupied ones. Air tightness tests are to be carried out on all residential developments (all the buildings or a selected group) and all certain Non-Dwellings. Non-dwellings where floor area is less than 500 m2 or has an assumed assessed air permeability rate of 15 m3/h/m2 in their calculations, may not have to undergo the air leakage test.
ATTMA has a competent scheme for air leakage testing firms which determines their level of competence. The scheme, which was launched in January 2015, is recognised by the government and noted in the building regulations. Minimum Technical Competence (MTC) and National Occupation Standard (NOS) documents are the basis for the scheme.
Test reports are issued by registered and licensed air tightness companies who test buildings of different sizes and complexities. Temporary sealing of extraction units will be done by the tester; all test results will be noted, and a shortened form report will be written which will include the findings of the test. This is done according to the testing organisation’s procedures and Building Regulation standards.
AF Acoustics will make sure the result is written in line with test requirements, detect any part of the test that is not in line with the standards required and check actual air tightness against required rate. The identity of the customer, tester, building and address are correctly written in our report. If a building fails the test, we provide remedial suggestions before a retest is carried out.
Before we arrive on site, ensure you have sent us the air permeability target and been through the checklist below and the ones we have sent you. This will greatly facilitate the process.
Air Permeability Pathway List – We will inspect every part for the building envelope for leaks.
Air leakage is the uncontrolled flow of air through gaps and cracks in the fabric of a building (sometimes called infiltration or draughts).
This is not to be confused with ventilation. Which is the controlled flow of air into and out of the building through purpose-built ventilators that are required for the comfort and safety of occupants.
Too much air leakage leads to unnecessary heat loss and discomfort to the occupants from cold draughts.
At AF Acoustics, we will endeavour to help you identify air leakage/infiltration paths.
There are a number of methods we employ to do this, including:
In the vast majority of cases the first two methods are sufficient to identify the most significant air leakage paths along with our expertise we will be able to point our the problem areas should they arise. The air leakage areas will have to permanently sealed and the test repeated to reduce the air permeability of the building. Where problems are larger and sealing cannot be addressed on the day, the building may need to be re-tested at a later date.
A test certificate from The Air Tightness Testing and Measurement Association (ATTMA)
A testing procedure is to be carried out to comply with TSL1 for domestic or TSL2 for commercial. The test certificate will include sufficient information to describe the building tested e.g. location, type and size (the envelope area is an important component in calculating the air permeability and must be accurate) plus the design air permeability as well as the actual result. A testing procedure should be representative of the actual building performance.
An indicative result is available at the time of testing. Certificates can be issued within a day of testing.
If required, you can request all calculations including pre, and post environmental measurements, individual static pressures, envelope area breakdown, flow readings and calibration certificates at no extra charge.
Air permeability is essentially a function of the pressure difference between the inside and outside of the building and the air flow rate through the fan(s), necessary to produce a pressure difference. This is averaged out over the envelope area. The result takes account of environmental conditions.
The final air permeability at 50 Pa is based on a logarithmic graph of pressure difference and flow rate, the graph should:
These are aspects that the building control should check carefully if choosing to accept air permeability results from non-accredited testing bodies.
Most air tightness tests for domestic units and simple commercial units are carried out in 45 – 60 minutes. This time may be extended if the test fails and leakage paths are investigated. We will normally charge for a retest depending on how much work is to be carried out.
On larger commercial units, which require 1 large air test fan, air tests take 1 hour if all temporary sealing has been completed prior to starting the air test.
If complicated or very large buildings are being air tested with multiple fan units, allow up to 4 hours for the test and longer if investigations are required.
The envelope area is calculated from the drawings and verified on site. The envelope of the building is all the surfaces that separate the heated interior from the unheated exterior of the dwelling. This includes walls, floors and the roof.
Generally, this involves mounting a door profile and incorporating one or more electrical fans into an external door opening(s). Depending on their orientation, the fans can be used to pressurise or depressurise the building. The resulting difference between the external and internal pressure can be used to calculate the permeability of the building envelope (given that the envelope area is known).
This permeability is an indicator of how air tight the building is, and whether there are openings in the envelope. Generally, 10 differential pressure points are taken at different fan flows to establish an accurate result for the building. Our certified specialised software is used to establish an accurate Air Tightness Test result.
Our experts at AF Acoustics will provide a simple checklist for building preparation, which includes the following:
All building preparations should be made before our test engineers arrive on the site this will ensure a smooth testing process and increase your dwelling’s chances of passing the test the first time. We will seal all the vents ourselves.
For multiple dwellings it may also be necessary to agree on the test programme with the building inspector before arriving on site.
Where possible, it is helpful to accurately calculate the envelope area and confirm the fan installation arrangements based on architectural drawings before coming to the site.
For dwellings, sufficient information is required to identify the different dwelling types and the number of each such as General Arrangement/Site Plan and Schedule (including other important details such as variation in storey height or construction method).
For buildings other than dwellings, the approximate envelope area is the key factor for quoting. It is required to establish the necessary fan arrangement. This affects the time on site and potentially the number of people, and this can be calculated from drawings – floor plans and elevations.
The testing body may also need to identify the potential aperture(s) into which test equipment is to be installed. In some circumstances this may require additional time on site, extra people or customised templates.
Approved Document L states that Building Control can accept evidence from BINDT or ATTMA Registered testers. However, the BINDT scheme was closed down at the end of 2014, subsequent to the last revision of Approved Document L. Additionally, The Independent Air Tightness Testing Scheme (iATS) is an authorised Competent Persons Scheme created for companies (including sole traders and partnerships) that carry out Air Tightness Testing.
The common leakage sites are:
All pipe works within the kitchen and bathrooms
Our team of experts can support you through the following
Additional AF Acoustics services – including noise survey, sound insulation testing services noise impact assessments
Employing the services of a reputable and accredited air tightness testing consultant, such as AF Acoustics, can help identify and remedy potential problem details in a building design prior to and during construction.
The Air Tightness Testing and Measurement Association (ATTMA) is approved by Department for Communities and Local Governments (DCLG) and is listed in the Building Regulations as an authorised Competent Persons Scheme for air tightness testing.
As an ATTMA registered company, AF Acoustics is independently certified by ATTMA with a scope covering air tightness testing to the ATTMA Technical Standards (TSL1 & TSL2) and BS EN: 13829 (2001), demonstrating knowledge and understanding, which enables us to test both commercial and domestic developments in accordance with relevant building regulations.
Part L sets the energy efficiency standards required by the Building Regulations. It controls:
It also sets out the requirements for SAP (Standard Assessment Procedure) Calculations and Carbon Emission Targets for dwellings. In addition to insulation requirements and limitations of openings of the building fabric.
Part L also considers:
Building Regulations are administered separately in England, Scotland and Wales.
The objective is to measure the volume of conditioned air escaping through the building envelope via uncontrolled ventilation at an induced pressure difference of 50 Pa. A simplified process is shown below:
No. However due to the penalties occurred to the air permeability value of non-tested properties, every property is usually tested. We can test all dwellings, including domestic buildings, industrial units, warehouses, schools, hospitals, residential care homes, hotels, offices, and retail units.
All new buildings and dwellings should be tested, but there are some exceptions and they are explained below:
No. Air tightness testing applies to:
Air tightness is an important factor in assessing the overall carbon emission of a building via the appropriate calculation methodology:
When a building is air tight, the amount of fuel needed to heat it is reduced. This conserves fuel and reduces the carbon dioxide produced, thereby lowering carbon emission and energy bills.
If you are building a new domestic property or commercial property of a certain size, it will need to undergo air tightness testing. This assesses the building for ‘air permeability’, checking for air leakage through gaps, holes and other areas. The Government has SAP (Standard Assessment Procedures) in place for air tightness testing, setting standards buildings must comply with to be energy efficient.
All residential properties and non-dwellings properties over a certain size (with a floor area greater than 500 m2) must undergo air tightness testing. With larger developments, a sample number of the buildings must be tested, depending on the size and construction of the properties. However, in practice all dwellings are likely to be tested, as non-testing attracts a severe penalty.
In a property where air tightness is below the recommended standard, the following problems can occur:
AF Acoustics lead air tightness testing Specialist, Gerard is your first port of call for all air tightness questions enquiries and surveys.
